Our invention relates to a process for making a product gas from a finely-divided carbon-bearing substance and, more particularly, from a finely-divided to powdery coal.
An apparatus for producing a product gas from a finely divided carbon-bearing substance, especially from a finely-divided to powdery coal, in the course of a high-pressure gasification comprising a vertical gasifier and radiative cooling device through which a flow occurs from bottom to top, a vertical convective cooling device through which a flow occurs from top to bottom and a connecting pipe between the head of the gasifier and radiative cooling device and the head of the convective cooling device. The gasifier and radiative cooling device has a shaft, which is circular in horizontal cross section and formed like a pipe, a lower cinder outlet and an upper conical connecting piece for the connecting pipe and is set up for cooling the fluidized cinder particles traveling with the product gas until they are solid and the convective cooling device is equipped with a lower outlet for the product gas and accompanying cinder particles. The product gas is a crude product and is subsequently purified. It comprises carbon monooxide and water and is used as a synthetic gas for making hydrocarbons, such as a heating gas, particularly for a gas turbine of a gas and steam turbine power plant, or as a reducing gas for metallurgical purposes. In regard to the chemistry and physics of high-pressure gasification, carbon high-pressure gasification is generally taught in the technical literature. The product gas allows the gasification step to proceed at a temperature of from 1300.degree. to 1700.degree. C. The appropriate devices are provided for the feed, transport and delivery of the flow rates of the species participating in the process.
In the known apparatus as described in European Pat. No. 0 115 094, on which our invention has been based, the shaft is provided with a quenching device for the direct feed of a foreign cooling agent (as steam, cooled product gas and the like) in connection with the gasification step. Here the product gas is cooled to such an extent that the cinder particles accompanying the product gas are almost completely solidified and no longer adhere to each other. In the radiative cooling portion a foreign cooling means is supplied indirectly. The register for the superheated steam is located there. After that the product gas enters into the connecting pipe. The known features are open to criticism: The problems, which occur in operation of the plant or apparatus, are on the one hand gas dynamic in nature and thus subject to the Laws of Aerodynamics and also the Laws of Thermodynamics. Also chemical kinetics provides an understanding of the process in the flowing gases as well. The aerodynamics and thermodynamics of the flow are controlled by their own boundary conditions and those boundary conditions are not immediately effected by the chemistry in the flow. In the above-described example the physical phenomenon are complex and the operation is barely optimizable and various operating parameters are scarcely adjustable. Disturbances in production losses resulting from energy losses must be taken into the bargin, i.e. considered. Besides the conveying action of the gas flow in regard to the accompanying cinder particles along the path of the flow of product gas from the gasification step to the outlet of the convective cooling device is by no means guaranteed.